Communications and other electronic products are often mounted in welded steel frame structures which have large height to width and height to depth ratios. The frame structures are often structurally secured only to the floor of a building and often have fundamental resonant frequencies within the bandwidth which contains high levels of seismic motion. The frames must be constructed with sufficient rigidity to resist permanent damage and/or damage to the frame mounted electronic equipment which could be caused by a resonant response to a seismic event.
In addition, requirements are often encountered which dictate certain maximum levels of electromagnetic emissions from the electronic equipment. This often leads to the use of electromagnetic emissions mitigating gasketed metal doors and covers mated against smooth planar exterior frame surfaces. Prior known electronic equipment frames employed external overlapping tabs at the interconnections between vertical upright frame members and the top frame member and/or base frame member of the equipment frame. Use of these overlapping tabs resulted in a non-smooth external surface which did not lend itself to use of such electromagnetic emissions mitigating gasketed doors and covers.